With tuition rates soaring, U.S. universities and colleges have an opportunity to cap their heating and cooling costs by looking to the earth beneath their feet.

That's according to a new report from the National Wildlife Federation, called "Going Underground on Campus: Tapping the Earth for Clean, Efficient Heating and Cooling." The analysis -- which considers 160 educational institutions that have invested in geothermal technologies, finds that these campuses are helping cut energy costs by 30 percent to 70 percent through a combination of the following:

Ground-sourced heat pumps

Buildings sheltered by the earth

Direct geothermal energy usage

Thermal energy storage

Electricity generated by geothermal sources

The report further estimates that if all of the nation's 4,100 colleges and universities used some form of geothermal technology, the energy savings could start at $2 billion annually. That calculation assumes that the average campus has energy costs of approximately $5 million per year.

An example: Ball Ball State University in Indiana is figuring to save about $2 million annually by using geothermal heat pumps to replace coal-fired boilers. This is focused on climate control (not electricity generation).

The 74-page report authors write:

"On its face, the implication of geothermal technologies might suggest application one building at a time, but such incremental steps only diminish the chance to capture the longer-term gains of campus-scale energy management. The better strategy for implementation over time requires a whole-systems vision and scheduled integration of campus-wide geothermal technologies."

The commonality that makes higher education institutions well-suited for geothermal: They usually have significant land acreage under their direct control, which is a critical consideration for geothermal activities.